A method and device for improving blood circulation in lower limbs of a patient have previously been described in our international patent application WO2006/054118. The contents of this publication are incorporated herein by reference.
This publication describes a device for improving blood circulation in a lower limb of a patient, the device comprising at least one electrode for administering an electrical stimulus to opposed leg muscles of a patient; a power supply connectable to the electrode; and a control means for activating the electrode to administer an electrical stimulus to the muscles sufficient to cause the muscles to contract isometrically. The stimulus may be applied directly or indirectly to the muscle. The muscles may be calf muscles, or may be the ankle and/or foot musculature.
The device operates by providing electrical stimulation to the lateral popliteal nerve in the region of the popliteal fossa. Additional stimulation may be applied to the medial popliteal nerve. Stimulation of the lateral popliteal nerve, in the region of the popliteal fossa, has the advantage of initiating the contraction of both posterior and anterior lower limb muscle groups. Such simultaneous stimulation results in isometric contraction; hence the ankle and knee joints would not be typically mobilised, while the muscle contraction is however sufficient to mobilise the so-called “calf pump” which aids in improving blood circulation in the lower limb. Stimulation of the lateral popliteal also elicits contraction of the foot muscles and hence the so-called “foot-pump” thereby further stimulating emptying of venous blood and enhancing blood flow. Additionally, the surprising advantage of selective stimulation of the lateral popliteal nerve is that the resultant muscular contractions are entirely compatible with standing and walking. An additional benefit of this mode of indirect stimulation is the involvement of the muscles in the sole of the foot, which have been shown to contribute substantially to clearance of blood from the lower leg.
In view of the fact that such isometric stimulation arising from simultaneous contraction of anterior and posterior muscle groups does not result in gross limb movement, and is intended to be compatible with walking, it has not hitherto been considered desirable to apply such stimulation to immobilised limbs.
However, we have now surprisingly discovered that application of isometric stimulation to an immobilised limb dramatically improves the increase in blood flow, and in particular promotes microcirculation in the limb.
U.S. Pat. No. 4,586,495 to Petrofsky describes a device for stimulating muscular activity in a patient with spinal cord injury. The device includes an external brace for applying to a leg, and a number of electrical stimulators. The leg muscles are stimulated, and the brace restrains movement. The system alternately stimulates agonist and antagonist muscles, which is necessary to allow the brace to resist movement.
US 2005/0043659 to Challis describes an apparatus for treating long bone fractures. An inflatable cuff is placed around the limb to provide compression of the fracture and surrounding musculature. Alternatively, electrical stimulation of the muscles may be used to compress the fracture.
GB 2 426 930 to Duncan describes a support for lower leg trauma patients which includes a base plate to provide support to the ankle, and electrical stimulation points to stimulate muscle contraction of the ankle and reduce muscle wastage.
GB 1 527 233 to Bleach describes an electrical stimulation device having a hollow shell which may be secured around the body part to be treated.
US 2007/0060975 to Mannheimer describes an electrical stimulation device operated as a TENS device for reducing pain, which may be used in combination with a splint, brace, bandage, or cast.
US 2004/0249432 to Cohen describes a surface electrode for skin stimulation of a patient.
U.S. Pat. No. 4,445,518 to Eggli describes a flexible areal electrode for use with a cast, and the use of holes in the cast and a filament for engaging with the electrode, designed to allow the electrode to be located within the cast.